Access to the Astrophysics servers is limited to ssh and sftp/scp only, you will need an ssh client to connect. There is no telnet, ftp, anonymous ftp or rlogin access.
Information on downloading and installing an SSH client for most operating systems can be found at http://help.phys.unsw.edu.au/ssh.php
Here small selection of commands to help get you started in unix.
To ssh to a server, eg astro
To copy directories recursively with permissions retained
From a server:
scp -rp email@example.com:/home/username/dir .
To a server:
scp -rp dir/ firstname.lastname@example.org:/home/username/